Heat sealing on multiple angled container flanges

ABSTRACT

A container ( 10, 64 ) for food and non-food products, the container including a circumferential flange ( 12, 22, 32, 40, 66 ) extending around the container, the flange including a plurality of angled surfaces ( 14, 16, 18; 24, 26, 28, 30; 34, 36, 38, 42, 44, 46; 68, 70, 72: 76, 77, 78 ) formed in the flange, and a closure member adhered to the plurality of angled surfaces for hermetically sealing said container. Also, a method for sealing containers for food and non-food products, wherein the method includes the steps of: a.) providing a container ( 10, 64  ) having a circumferential flange ( 42, 22, . . .  ). b.) forming a plurality of angled surfaces ( 14, 16, 18; . . .  ) in the circumferential flange extending about the circumference of the container, c.) placing a closure member ( 20, 74 ) over the circumferential flange, d.) supporting the flange and the closure member in a nest ( 52, 56 ): e.) and applying at least one heated anvil to the closure member for causing the closure member to conform to and adhere to the plurality of angled surfaces in the circumferential flange.

BACKGROUND OF THE INVENTION

There are two well accepted ways to heat seal lids or end panels onto containers for solid, liquid, or combination products for food and other products. Typical, containers may be in the form of annular cans that are circular in cross section, or may be oval shaped container's usually referred to as tubs, or may be bottles of metal, glass or blow molded plastic. One sealing process uses induction heating, and the second heating process uses heated anvils or sealing heads. Both processes arc used frequently, and both could have either internal or external flanges serving as sealing surfaces on the container.

External Flanges:

A considerable amount of prior art in this field is shown in my earlier U.S. application Ser. No. 11/362,008, now abandoned, and patents to Helms (U.S. Pat. No. 5,991,334) and Ramsey (U.S. Pat. No. 5,723,129), which deal with external flanges and internal flanges and in all cases only one sealing surface is described.

An internal lacing flange can most likely occur on a blow molded package such as a bottle. Most such bottles have external threads or snap rings and a foil or film is heat sealed to the top edge of the finish or a flange. The closure, i.e., lid or end panel, provides tamper evidence and/or an oxygen barrier. The structural work, augmenting the seal and holding the foil or film in place during the filling process, vacuum, or pressure, or drop impact, is done by the closure.

SUMMARY OF THE INVENTION

For “internal flanges” using the sealing concept, disclosed herein, creates a strong, peelable seal, performs all of the functions required and may, or may not utilize a “dust cover” or a reclosing, additional lid. The net result is a desirable material saving in the flange (no threads and a shorter height), a lower cost closure, and an improved peelable seal.

For “external flanges”, the present invention utilizes a plurality of three or more sealing surfaces which provide strong benefits for closing and sealing containers.

In addition, the invention provides a container and closure member having increased burst strength, and improved resistance to failure under pressure and vacuum conditions resulting from retorting of the product.

Depending upon the flange angles, the foil or film closure member may be preformed, or is reformed by the complementary shaped angles on the heat sealing tool and tool nest in order to prevent wrinkling when the closure member is placed over the container flange and beat sealed thereto.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a container utilizing a closure member in accord with the invention.

FIGS. 2-5 illustrate fragmentary profiles of containers having outwardly extending external flanges.

FIGS. 6 and 7 show tooling for affixing foil or films to external flanges.

FIG. 8 illustrates tooling for affixing foils or film to containers having an inwardly and upwardly extending flange.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a container, generally indicated by the numeral 10, for utilizing a closures member in accord with the invention.

In FIG. 2 an outwardly extending flange 12 of a container includes a first horizontal sealing surface 14, a second horizontal sealing surface 16 and a third sealing surface comprised of an outwardly and downwardly angled sealing surface 18 for placing a foil or film closure member 20 (shown in FIGS. 6 and 7) in shear, rather than in peel.

In FIG. 3 an outwardly extending flange 22 of a container includes a first horizontal sealing surface 24, a second horizontal sealing surface 26 arid an outwardly and downwardly angled sealing surface 28 for placing a foil or film closure 20 (shown in FIGS. 6 and 7) in shear rather than in peel. Flange 22 also includes a peripheral lip 30 that assists in peeling the closure when opening the container 10.

In FIG. 4 an outwardly extending flange 32 of a container includes a first horizontal sealing surface 34, an outwardly and downwardly angled sealing surface 38, and a second angled surface 38 forming a slightly less angle than that formed by sealing surface 36 for placing a foil or film closure 20 (shown in FIGS. 6 and 7) in shear rather than peel.

In FIG. 5 an outwardly extending flange 40 of a metal container 100 includes a first horizontal sealing surface 42, a second horizontal sealing surface 44 and an outwardly and downwardly angled sealing surface 46 for placing a foil or film closure member 20 (shown in FIGS. 6 and 7) in shear. A reversely turned peripheral edge 48 is provided for protecting the user from a sharp metal, edges

FIG. 6 illustrates a heat seal tool 50 and a nest 52 for heat sealing a foil or film closure to a plastic container having a flange 22 as is shown in FIG. 3.

FIG. 7 illustrates a heat seal tool 54 and a nest 56 for heat scaling a foil or film closure to a plastic container having a flange 12 as is shown in FIG. 2. Nest 56 differs from nest 52 by having an uppermost, horizontal surface 58.

FIG. 8 illustrates a sectional view of a heat tool 60 and a support ring 62 that, encircles a blow molded bottle 64 having a flange 66 extending inwardly toward a center line C/L of the container 64. Flange 66 includes a first horizontal sealing surface 68, a second horizontal sealing surface 70 and an upwardly angled sealing surface 72 for placing a roil or film closure member 74 in shear rather than in peel. The foil is provided with an heat activated adhesive layer 75.

The foil or film closure members 20 and 74 can be preformed with angles corresponding to the angles in the associated container. This feature provides additional protection against deleterious wrinkles being form in the foil or film during attachment, and sealing to the container flange and me angles contained therein.

The various flanges include an uppermost horizontal flange 14, 24, or 34. These horizontal surfaces add stability, stiffness to support the flange during sealing, and a vertical stop for the downstroke of the heat conduction tool.

Additionally, the outermost horizontal angles 16, 26, 44 and 70 provide for better trimming from the web—always 90 degrees from the center line and in the up and down direction of the trimming press stroke.

The angled surfaces 18, 28, 36, 46 and 72 may form a small or large angle with the vertical. A useable range would be on the order of about live degrees to about sixty degrees, with a preferred range on the order of about 15 degrees to about 60 degrees.

The benefit of the foregoing invention and embodiments thereof will be readily apparent from a consideration of the following test data comparing container closures that have been heat sealed in shear, and current prior art processes that attach closures in a horizontal, flat plane.

Bursts Tests: Heat Seal in Shear (Angled) vs. Peel (Flat)

-   307 Diameter Plastic Bowls with Sealing Film Heat Sealed to the     Flange -   Standard Plant Air -   Test Results:**

Pounds per Square Inch (PSI) Variable Flange Angle Average Burst Burst Range Flat (Control) 26 18-32 30 Degree Angle 45 41-55 45 Degree Angle 56 53-65 **Note: In the same tests, aluminum EZO ends (Easy Open Ends) Buckle or fail in the 40-45 psi range.

It is to be understood that the methods and embodiments disclosed herein are meant to be exemplary, and various modifications may be made within the scope of the appended claims. 

I claim:
 1. A method for sealing containers for food and non-food products, said method including the steps of: a.) providing a container (10, 64) having a circumferential flange (12, 22, 32, 40, 66), b.) forming a plurality of at least three angled surfaces (14, 16, 18; 24, 26, 28, 50; 34, 36, 38; 42, 44, 46; 68, 70, 72; 76, 77, 78) in said circumferential flange extending about the circumference of said container, c.) placing a closure member (20, 74) over said circumferential flange, d.) supporting said flange and said closure member in a nest (52, 56); e.) and applying a heated anvil to said closure member for causing said closure member to adhere to said plurality of angled surfaces in said circumferential flange.
 2. The method as defined in claim 1 wherein said closure member includes heat activated adhesive on a surface facing said circumferential flange.
 3. The method as defined in claim 1 wherein said closure member is comprised of heat sensitive thermoplastic.
 4. The method as defined in claim 1 wherein said closure member is comprised of metal foil and an adhesive layer on a side thereof facing said flange.
 5. The method as defined in claim 1 wherein said annular flange extends outwardly of said container.
 6. The method as defined in claim 1 wherein said annular flange extends inwardly of said container.
 7. A container for food and non-food, products, said container (10, 64) including an annular flange (12, 22, 32, 40, 66) circumscribing said container, said flange including a plurality of at least three angled surfaces (14, 16, 18; 24, 26, 28, 30; 34, 36, 38; 42, 44, 46; 68, 70, 72; 76, 77, 78) formed in said flange, and a closure member (20, 74) adhered to said plurality of angled surfaces for hermetically sealing said container.
 8. The container as defined in claim 7 wherein said flange (40) is made of metal and an outer periphery of said flange is folded back upon itself to eliminate an outermost raw edge.
 9. The container as defined in claim 7 wherein said flange extends outwardly of said container.
 10. The container as defined in claim 7 wherein said flange extends radially inwardly of said container.
 11. The container as defined in claim 7 wherein said closure member is metal foil and includes an heat sensitive material on a side thereof facing said flange.
 12. The container as defined in claim 7 wherein said closure member is comprised of a thermoplastic material.
 13. The container as defined in claim 7 wherein said closure member is preformed for conforming to said angled surfaces in said annular flange.
 14. A combination comprising a container, said container having a plurality of circumferential extending angular flanges formed therein adjacent an open end thereof for providing sealing surfaces, a closure member for closing said open end, and one or more heat sealing tools having angles formed therein, complementary to said sealing surfaces.
 15. The combination defined in claim 14 wherein said closure member includes preformed angular sealing surfaces complementary with said container angular flanges and said angles in said heat sealing tool.
 16. The method as defined in claim 1 including the step of causing said closure member to conform to said plurality of angled surfaces in said circumferential flange during the step of applying said heated anvil to said closure member. 